I have just bought what i have been led to believe is a Stage 3 T3 for an RS turbo, it has been built by CR turbos and aledgedly has a 360 degree thrust bearing and the all important .48 cosworth exhaust housing. However i have visually compared it against my standard RST exhaust housing and to me it looks identical, there are no numbers/markings on my new housing so how can i work out if it IS a cossie housing?
The only markings i can see are 'CR turbos' on the compressor back plate and actuator

Also it is supposed to have a bigger compressor but this too looks identical to my spare one, both have .42 stamped on them. If i was to strip both units down and measure at various points, what areas do i need to measure or is there anything that will be obvious that my new turbo is what its described to me